Cable winch

ABSTRACT

A cable winch, particularly for scaffolds, comprising a housing and a driving pulley mounted for rotation within the housing and around which pulley the cable passes. A flexible contact-pressure element attached by one end to the housing presses the cable against the driving pulley over a contact angle of more than 180*. The contact-pressure element is responsive to the load applied to the cable whereby an increase in load increases the contact-pressure applied by the element to the cable, and viceversa.

[ 3,721,426 1March 20, 1973 United States Patent [54] CABLEWINCH3,231,240 H1966 Naito.........t...l.....4.. ....4.......254/l91 76Inventor: C Kaufer, Kupfbrberg, 3,520,515 7/1970Pomagalskl..........l............254/l75.5

near Wipperfurth, Germany July 8,1971

Primary Examiner-Harvey C. Hornsby Att0rney-Hubert T. Mandeville et al.

[22] Filed:

ABSTRACT [21] Appl. No.: 160,621

[30] Foreign Application priority Data A cable winch, particularly forscaffolds, comprising a housing and a driving pulley mounted forrotation Aug. 25, 1970 Germany...................V.P 20 41 993.6

within the housing and around which pulley the cable passes. A flexiblecontact-pressure element attached by one end to the housing presses thecable against the driving pulley over a contact angle of more than 180.

0 m 7] Id 46 56 B 7 6 l 4 5 Field of Search.......................

167 The contact-pressure element is responsive to the load applied tothe cable whereby an increase in load in- [56] References Clted creasesthe contact-pressure applied by the element to the cable, and viceversa.

UNITED STATES PATENTS 3,100,626 8/1963Good.....................v...........254/175.5 6 Claims, 1 DrawingFigure CABLE wmcn BACKGROUND OF THE INVENTION The invention relates to acable winch, particularly for scaffolds, having a driving pulley whichisaccommodated in a housing and around which pulley the cable passes andagainst which it is pressed by means of a flexible and adjustablecontact pressure element affixed by one end to the housing. Inparticular, the invention relates to a motor-operated cable winch havinga driving pulley unit, for the vertical transport of passengers, for usewith so-called scaffolds.

With cable winches intended for use with scaffolds it is desirable forthe cable to be passed around a driving pulley in such a way that thecable cannot slip out of place in relation to the pulley. For thispurpose the cable has hitherto been placed in a number of turns aboutthe driven pulley, a method which, however, involves a number ofdrawbacks. In particular, the pressure of the cable against the pulley,in such a winch, cannot be varied in accordance with the load applied tothe cable, and automatic retraction of the cable into the winch islikewise impracticable.

PURPOSE OF THE INVENTION which the cable can be retracted automatically.

SUMMARY OF THE INVENTION The invention proposes, for the performance ofthe task required, that with such a cable winch the flexible contactpressure element should embrace the driving pulley by more than I80 andvary the force of its pressure on the cable in proportion to the loadapplied to the cable. In a construction of this kind the cable need onlybe taken around the driving pulley once, not even a complete turn beingrequired, so that the retraction of the cable into the winch can becarried out without difficulty and therefore automatically.

In a preferred construction of the invention the contact-pressureelement is connected by its free end to a tensioning element whosetension is adjusted by the load applied to the cable. This tens ioningelement may consist of a cable deflector roller which is mounted in aneccentrically pivotable manner at the cable inlet and which is attached,eccentrically in respect of the pivoting point, to the free end of theflexible contacbpressure element. When the load applied to the cablewinch increases, the pressure of the cable placed around the deflectorroller is eccentrically pivoted and pulls the flexible contact-pressureelement in the process, so that the latter presses more firmly againstthe driving pulley and thus against the cable passing around the drivingpulley. In this manner the deflector roller can also be subjected to theaction of a spring tending to draw it away from the driving pulley, as aresult of which a predetermined minimum contact-pressure force by thepressure element is ensured.

According to a further characteristic of the invention, a fixed cableguide system interacting with the deflector roller is affixed at thecable inlet and facilitates the passage of the cable through the winch.

This cable guide system can interact with an adjustable cable-lockingdevice, preferably provided at the cable outlet.

The flexible contact-pressure element is preferably equipped withnumerous contact-pressure rollers which, via a flexible element,preferably a chain or a cable guide system, are connected with oneanother and with the eccentrically pivotable contact-pressure roller.This ensures that the contact-pressure element will make contact over anample length of the cable passing around the driving pulley, whileproducing comparatively little friction. The contact-pressure force isthus transmitted to' the cable in a manner largely free of loss.

For drive purposes the driving pulley has an internal system of gearteeth engaged by a drive pinion of a driving gear. The latter can bedirectly connected to a drive motor, which is mounted on the cable winchitself. For reasons of safety, moreover, a hand crank can be connectedwith the gearing, so that the winch can be operated even if the motorfails.

BRIEF DESCRIPTION OF DRAWING The drawing shows in cross-section a cablewinch constructed in accordance with the teachings of the invention.

DESCRIPTION OF SPECIFIC EMBODIMENTS A cable winch comprises a housing 1and a driving pulley 3 mounted in the housing so as to be rotatableabout a central shaft 2 and having a flange-connected internally-toothedring 4 engaged by a driving pinion 5 of a driving gear which is mountedon the rear of the housing 1 and which is therefore not shown in detailin the drawing. The driving gear can be connected with a driving motor,likewise not shown. The driving gear preferably consists of a worm gearwhich, to assist the self-locking action of the gear, can be providedwith a brake 6. In case the driving motor should fail, a hand crank 7can be attached to the gearing, enabling the entire cable winch and thescaffold attached to it to be let down.

The driving pulley 3 is provided on its outer periphery with a groove 8into which a cable is pressed by a contact-pressure element 10. As maybe seen from the drawing, the cable 9 only passes round the drivingpulley 3 once, the inlet and the outlet of the cable being closetogether in the upper zone of the winch. Between the ingoing end and theoutgoing end of the cable, moreover, is a fixed cable guide system 11,which likewise comprises grooves 12 and 13 for the lateral guiding ofthe cable 9. In the drawing, the cable inlet is on the right and thecable outlet on the left.

In the example shown the contact-pressure element 10 consists of a linkchain 14 with numerous contactpressure rollers 15. The right-hand end ofthe link chain 14 is affixed to a fixed link pin 16 in the housing 1,while the left-hand end of the link chain 14, passing around the drivingpulley 3 by more than is flexibly affixed to a bar 17 which in turn isflexibly connected to a lever 18 pivotably suspended around a fixed pin19 in the housing 1. The lever 18 is also subject to the action of atension spring 20 which ensures a certain minimum pressure of thecontact-pressure element 10 against the cable 9 passing around thedriving pulley 3.

Approximately in the center of the lever 18, a deflector pulley 21,acting against the ingoing end of the cable, is rotatably mounted insuch a way that the deflector pulley can be pivoted, with the lever 18,about the pin 19 serving as an eccentric pivot. If a load, such as ascaffold, is suspended on an eyelug 22 provided at the bottom of thehousing 1, then the cable will exert against the deflector pulley 21 apressure the magnitude of which will depend on the size of the load thusapplied to the cable 9, because the cable tends, under the influence ofthe load applied, to assume a straight position. As a result, the cablepresses the deflector pulley 21 to a greater or smaller distance towardsthe right, in which process the deflector pull'ey 21 is pivoted aboutthe pin 18 and thus, via the bar 17, exerts on the contact-pressureelement a tractive force which will exceed that of the spring 20. Thisin turn causes a greater contact-pressure force to be exerted on thecable passing around the driving pulley 3, so that the former isreliably prevented from sliding over the latter. On the contrary, thecable will be firmly pressed into the groove 8 of the driving pulley, asa result of which the load attached to the eyelug 22 can only be raisedor lowered when the driving pulley 3 is rotated via its drive motor.

In the vicinity of the cable outlet, a cable locking device in the formof an eccentrically mounted pawl 23, is movable into an engaged positionin which it locks the cable to the cable guide 1 1.

What is claimed is:

l. A cable winch, particularly for scaffolds, comprising a cable, ahousing, a driving pulley mounted for rotation within the housing andaround which pulley the cable passes, said driving pulley being providedwith a peripheral groove containing the cable, a flexiblecontact-pressure element attached by one end to the housing and pressingthe cable against the driving pulley over a contact angle of more than180, said contact-pressure element being responsive to load applied tothe cable whereby an increase in load increases the contact pressureapplied by the element to the cable and a decrease in load decreases thecontact pressure applied by the element to the cable, saidcontact-pressure element being attached by one end to a first pivot onthe housing and by its other end to a tensioning element responsive tothe load applied to the cable, said tensioning element including adeflector pulley in rolling guiding contact with the cable and pivotableeccentrically about a second pivot located adjacent the driving pulleywhere the cable approaches the driving pulley, and wherein the other endof the contact-pressure element acts on the deflector pulleyeccentrically with respect to the second pivot, whereby an increase inload on the cable causes the cable to pivot the deflector pulley aboutthe second pivot in a direction away from the driving pulley, therebyincreasing the contact pressure applied to the cable by thecontactpressure element.

2. A cable winch as claimed in claim 1, wherein the deflector pulley issubjected to the action of a spring tending to draw the deflector pulleyaway from the driving pulley so as to maintain a predetermined minimumcontact pressure by the contact-pressure element.

3. A cable winch as claimed in claim 1, including a cable guide meansfixed in relation to the driving pulley and gutding the cable into andout of contact WI h the driving pulley in co-operation with thedeflector pulley.

4. A cable winch as claimed in claim 3, further comprising a lockingdevice co-operating with the cable guide means and operable to lock thecable to the cable guide means.

5. A cable winch as claimed in claim 1, wherein the flexiblecontact-pressure element has a plurality of contact-pressure rollers.

6. A cable winch as claimed in claim 1, wherein the driving pulley hasinternal gear teeth meshing with a driving pinion of a motor-drivendriving gear.

1. A cable winch, particularly for scaffolds, comprising a cable, ahousing, a driving pulley mounted for rotation within the housing andaround which pulley the cable passes, said driving pulley being providedwith a peripheral groove containing the cable, a flexiblecontact-pressure element attached by one end to the housing and pressingthe cable against the driving pulley over a contact angle of more than180*, said contactpressure element being responsive to load applied tothe cable whereby an increase in load increases the contact pressureapplied by the element to the cable and a decrease in load decreases thecontact pressure applied by the element to the cable, saidcontact-pressure element being attached by one end to a first pivot onthe housing and by its other end to a tensioning element responsive tothe load applied to the cable, said tensioning element including adeflector pulley in rolling guiding contact with the cable and pivotableeccentrically about a second pivot located adjacent the driving pulleywhere the cable approaches the driving pulley, and wherein the other endof the contact-pressure element acts on the deflector pulleyeccentrically with respect to the second pivot, whereby an increase inload on the cable causes the cable to pivot the deflector pulley aboutthe second pivot in a direction away from the driving pulley, therebyincreasing the contact pressure applied to the cable by thecontact-pressure element.
 2. A cable winch as claimed in claim 1,wherein the deflector pulley is subjected to the action of a springtending to draw the deflector pulley away from the driving pulley so asto maintain a predetermined minimum contact pressure by thecontact-pressure element.
 3. A cable winch as claimed in claim 1,including a cable guide means fixed in relation to the driving pulleyand guiding the cable into and out of contact with the driving pulley inco-operation with the deflector pulley.
 4. A cable winch as claimed inclaim 3, further comprising a locking device co-operating with the cableguide means and operable to lock the cable to the cable guide means. 5.A cable winch as claimed in claim 1, wherein the flexiblecontact-pressure element has a plurality of contact-pressure rollers. 6.A cable winch as claimed in claim 1, wherein the driving pulley hasinternal gear teeth meshing with a driving pinion of a motor-drivendriving gear.